1. Field of the Invention
The embodiments discussed herein are relates to a method of making pattern data of a photomask used to manufacture a Large Scale Integration (LSI) circuit device, a program for making the pattern data, and a medium for storing the program.
2. Description of the Related Art
In the manufacture of an LSI circuit device, an element pattern forming a circuit has been desired to be miniaturized for higher integration. Further, in the formation of a minute pattern, to obtain a predetermined element characteristic, the element pattern needs to be formed on a semiconductor substrate as designed and with high accuracy. However, if a photomask pattern used to manufacture the LSI circuit device has not been formed in consideration of the optical proximity effect, the element pattern as designed cannot be formed on the semiconductor substrate in the transfer of the pattern onto the semiconductor substrate.
Therefore, to form a photomask pattern in consideration of the optical proximity effect, correction in consideration not only of rotation information, axis inversion information, and magnification information but also of Optical Proximity Correction (OPC) as it is called (OPC processing) has been performed on design data for forming the element pattern to make data used to form the photomask pattern.
The above-described OPC processing is performed on the design data for forming all element patterns on the basis of the space and the width of the element patterns and optical conditions. Therefore, if the number of pattern data items for forming the element patterns is large, the OPC processing requires a long period of time.
In view of the above, a proposal has been made to first determine the OPC processing for a first area, and then reuse the OPC processing for the first area in a second area having a pattern identical to the pattern included in the first area, to thereby reduce the time period required for the OPC processing (e.g., Japanese Patent No. 3343246).
Further, another proposal has been made to first register second cells obtained by the OPC processing previously performed on first cells which are formed by a plurality of element patterns and repeatedly used, and then replace the first cells with the second cells to perform the OPC processing on the entire design data, to thereby reduce the time period required for the OPC processing (e.g., Japanese Laid-open Patent Publication Nos. 2007-86587 and 2005-84101).
It is obvious from the above description that the time period required for the OPC processing can be further reduced, if it is possible to effectively identify particular areas or cells to be subjected to the OPC processing, and to effectively identify, among the areas or cells, a larger number of areas or cells considered to be equivalent in the purpose of the OPC processing.